ES2817827T3 - Balloon catheter - Google Patents

Abstract

A balloon catheter (1, 10, 100, 110, 130, 160, 170) comprising an inner tube (3, 103) having a first lumen (11, 111); an outer tube part (2) provided coaxially with said inner tube (3, 103) and forming a second lumen (12, 112) between said outer tube part (2) and an outer surface of said inner tube (3, 103); and a balloon part (4, 104), a front end zone of which is fixed to a front end zone of said inner tube (3, 103) and an interior of which communicates with said second lumen (12, 112) , said balloon part (4, 104) has a bulging area (40, 140), having an expansion formation mode formed in advance, which is elastically deformable beyond said expansion formation mode by an expansion liquid of balloon injected into it, said outer tube portion (2) has a front side sleeve area (21, 120) extending from a rear end area of said bulging area (40, 140) of said portion of balloon (4, 104) towards a proximal end of said outer tube part, is integrally formed with said balloon part (4, 104) by using the same material as that to be used for said balloon part (4, 104), and is substantially non-expandable, characterized in that said outer tube part (2) has a body pr incipal outer tube (22, 102) having a front end area attached to a rear end area of said front side sleeve area (21, 120), said front side sleeve area (21, 120) has a surface collapsed rear end (145) oblique to said central axis of the tubular zone (42, 142), said outer tube main body (22, 102) has a collapsed front end surface (121) oblique to said central axis of said main body of outer tube, said outer tube portion (2) has a belt-shaped collapsed annular attachment area (106) formed by attaching an overlapping area of said rear end area of said front side sleeve area (21, 120) and said front end zone of the outer tube main body, and said belt-shaped collapsed annular fixing zone (106) is oblique to a central axis of said tubular zone (42, 142).

Description

DESCRIPTION

Balloon catheter

Technical field

The present invention relates to a balloon catheter and more particularly to a balloon catheter to be inserted into a blood vessel to occlude the blood vessel.

Background of the technique

The balloon catheter is used to perform angiography, inject a liquid medicine such as a chemotherapeutic agent into a blood vessel, and vascular embolization. A balloon catheter as described in patent document 1 (Japanese Patent Application Laid-Open Publication No. 2005-103120) has been proposed by the applicant of this application. The balloon catheter 1 of patent document 1 has the double tube-structured catheter main body 3 having the inner tube 9 and the outer tube 21. The balloon 3 is mounted on the catheter main body in its front end region. The injection liquid passageway 23 formed between the inner tube and the ^{outer tube communicates with the interior of the catheter main body through the opening} 22 ^{formed in the} forward end of the outer tube. A catheter provided with an expandable body is described in Patent Document 2 (Japanese Patent Application Laid-open Publication No. H09-10314). In the catheter with the expandable body, the outer tube 1 and the inner tube 2 are arranged coaxially. The outer tube 1 is constructed of ^{the flexible front end part} 11 ^{, the intermediate part} 12 ^{whose inside and outside diameters are greater than those} of the front end part 11, and the thick proximal end part 13 whose inside and outside diameters are greater than those of the of the intermediate part 12. The outer tube has the collapsible and contractible expandable body 10 at the front end part 11 thereof. The catheter is smoothly, integrally and seamlessly formed from the leading end portion 11 including the expandable body 10 to the proximal end portion 13.

Prior art documents

Patent documents

Patent Document 1: Japanese Patent Application Open to Public Inspection Publication No. 2005-103120 Patent Document 2: Japanese Patent Application Open to Public Inspection Publication No. H09-10314 (Publication No. JPH0910314) . Additional balloon catheters known from the prior art are described in WO9620752 and JP2011206171.

Compendium of the invention

Problems to be solved by the invention

Recently there is a demand for balloon catheters such as those described in patent document 1, that balloon catheters are thin and can be inserted into a curved blood vessel. The expandable body catheter ^{of patent document} 2 ^{is smoothly, integrally and seamlessly formed from the leading end portion} 11 ^{including the expandable body} 10 ^{to the proximal end portion 13 and having no change points at which the} properties of the materials used for the catheter change abruptly. The collapsible and contractible expandable body is used. But the catheter of patent document 2 is used to expand a narrow passage generated in a blood vessel and increase the flow rate of blood on the distal side of the narrow passage. To do this, the expandable body expands by injecting a liquid into it at high pressure.

The balloon catheter to be used for blood vessel embolization is required to safely occlude a blood vessel at low injection pressure by using elastic deformation of the balloon because the blood vessel into which the balloon catheter is inserted has a small diameter and is it should prevent damage to the inner wall of the blood vessel. Therefore, an object of the present invention is to provide a balloon catheter that can be inserted into a curved blood vessel having a small diameter and that allows a balloon to be safely expanded by low fluid pressure to thereby safely occlude the blood. The invention is defined by the appended claims.

Means to solve problems

The means to achieve the object described above are as described in independent claim 1.

Brief description of the drawings

Figure 1 is a partially abbreviated exterior view of an exemplary balloon catheter.

Figure 2 is an enlarged exterior view of a leading end area of the balloon catheter shown in Figure 1. Figure 3 is an enlarged vertical sectional view of the leading end area of the balloon catheter shown in ^Figure 1 ^{when a balloon expands.}

Figure 4 is an enlarged vertical sectional view of a proximal portion of the balloon catheter shown in Figure 1.

Fig. 5 is an explanatory view for explaining the exemplary balloon catheter.

^Fig. 6 ^{is an explanatory view for explaining another exemplary balloon catheter.}

Fig. 7 is an explanatory view to explain yet another exemplary balloon catheter.

^Fig. 8 ^{is an explanatory view for explaining a method of the present disclosure for measuring a} bending load value of three points per deflection unit.

Figure 9 is a partially abbreviated exterior view of the balloon catheter of the present invention.

Figure 10 is an enlarged exterior view of a leading end region of the balloon catheter shown in Figure 9.

Figure 11 is a vertical sectional view of Figure 10.

Figure 12 is an enlarged vertical sectional view of a proximal portion of the balloon catheter shown in Figure 9.

Fig. 13 is an explanatory view for explaining a firm fixation zone where a rear end zone of a balloon of the balloon catheter shown in Fig. 9 and a front end zone of the outer tube thereof are firmly fixed to each other.

Fig. 14 is an explanatory view for explaining the firm fixation zone where the rear end zone of a balloon of the balloon catheter shown in Fig. 9 and the front end zone of the outer tube thereof are firmly fixed to each other.

Fig. 15 is an explanatory view for explaining the firm fixation zone where the rear end zone of a balloon of the balloon catheter shown in Fig. 9 and the front end zone of the outer tube thereof are firmly fixed to each other.

Figure 16 is an enlarged view view of the vicinity of a firm fixation zone where a rear end zone of a balloon of a balloon catheter of an exemplary balloon catheter and a front end zone of an outer tube thereof are firmly attached. fixed to each other.

Figure 17 is a vertical sectional view of Figure 16.

Fig. 18 is an enlarged view view of the vicinity of a firm fixation zone where a rear end zone of a balloon of a balloon catheter of yet another exemplary balloon catheter and a front end zone of an outer tube thereof are firmly fixed to each other.

Figure 19 is a vertical sectional view of Figure 18.

Figure 20 is an enlarged sectional view of the vicinity of a firm fixation zone where a rear end zone of a balloon of a balloon catheter of yet another exemplary balloon catheter and a front end zone of an outer tube thereof are firmly fixed to each other.

Figure 21 is a view is an enlarged sectional view of the vicinity of a firm fixation zone where a rear end zone of a balloon of a balloon catheter of yet another exemplary balloon catheter and a front end zone of an outer tube of the same are firmly fixed to each other.

Figure 22 is a view is an enlarged sectional view of the vicinity of a firm fixation zone where a rear end zone of a balloon of a balloon catheter of yet another exemplary balloon catheter and a front end zone of an outer tube of the same are firmly fixed to each other.

Mode for carrying out the invention

The balloon catheter of the present invention is described below using embodiments shown in the drawings. An exemplary balloon catheter 1 has an inner tube 3 having a first lumen 11, an outer tube part 2 provided coaxially with the inner tube 3 and forming a second lumen between the outer tube part and an outer surface of the inner tube. , and a balloon part 4, a front end zone of which is attached to a front end zone of the inner tube 3 and an inner zone of which communicates with the second lumen 12. The balloon part 4 has a bulging zone 40, having a preformed expansion formation mode, which is elastically deformable beyond the expansion formation mode by a balloon expansion liquid injected thereto. The outer tube part 2 has a front side sleeve area 21 extending from a rear end area of the bulge area 40 of the balloon part 4 to a proximal end of the outer tube part, integrally formed with the balloon part 4 when using the same material as the one to be used for the balloon part 4, and is substantially non-expandable. In balloon catheters 1, 10 and 20 shown in Figures 1 to 7, each of the outer tube parts 2 thereof is formed entirely integrally with the balloon part 4 by using the same material as that to be use for balloon part 4. In balloon catheters 100, 110, 130, 150, 160 and 170 shown in Figures 9 to 22, each of the outer tube parts thereof is constructed of a ^{cuff zone of front side} 120 ^{and an outer tube main body} 102 ^{, a front end portion of which is attached to a rear end portion of the front side sleeve area} 120 ^.

The balloon catheter of one embodiment shown in Figures 1 to 7 is described below. The balloon catheter 1 ^{of this example is formed of the outer tube part} 2 ^{having the front side cuff area} 21 ^integral with the balloon part 4, the inner tube 3 and a branch connector 5. The inner tube 3 it is a tubular body having the first lumen 11, a front end of which is open. The first lumen 11 is used to insert a guide wire into the inner tube and inject a liquid medicine and the like into it. In the balloon catheter 1 of this example, the first lumen 11 of the inner tube 3 communicates with a first open area 54 provided in the branch connector 5. It is favorable to set the outer diameter of the inner tube 3 from 0.6 to 1, 7 mm and especially favorable to set the outer diameter thereof from 0.6 to 0.7 mm. It is favorable to set the inner diameter of the inner tube to 0.4 to 1.4 mm and especially favorable to set the inner diameter thereof to 0.4 to 0.50 mm. The inner tube 3 is inserted into the outer tube part 2 in such a way that a leading end zone thereof protrudes forward beyond the outer tube part 2. The second lumen 12 (balloon expansion lumen) is formed between the outer surface of the inner tube 3 and an inner surface of the outer tube part 2 and has a sufficiently large volume.

An imaging marker 32 is attached to the inner tube 3 at its leading end area (disposed slightly proximal from a leading end 31 of the inner tube and in the vicinity of a leading end area 42 of the balloon portion 4). It is preferable to form the imaging marker from a radiopaque material (eg, gold, platinum, tungsten or alloys of these metals or a silver-palladium alloy, a platinum-iridium alloy). ^{In doing so, it is possible to check the front end zone of the balloon catheter} 1 ^{by means of} radiographic visualization. The inner tube 3 may be provided with a stiffness-imparting body 35. As a stiffness-imparting body, a vane formed of a metal wire or a synthetic resin wire is preferable. In the case where the inner tube 3 is provided with the stiffness-imparting body, it is preferable to provide the stiffness-imparting body entirely on the inner tube except for the front end zone thereof, as shown in Figure 3. More specifically , it is preferable to provide the stiffening body on the inner tube in a range from the imaging marker 32 to the proximal end thereof.

In the balloon catheter of this example, as shown in Figure 1, the inner tube 3 has a first flexible region 3a arranged on a front side of the inner tube 3, a second flexible region 3b that is continuous with the first flexible region 3a and flexible but has higher toughness than the first flexible region 3a, and a flexible region 3c that is continuous with the second flexible region 3b and has higher toughness than the second flexible region 3b. In this example, as shown in Figure 1, the first flexible region 3a which is the most flexible extends rearwardly from the front end of the inner tube 3. A rear end of the first flexible region 3a is positioned rearwardly from the front of it a predetermined length. The length of the first flexible region 3a is favorably set at 100 to 350 mm and especially favorably at 200 to 300 mm.

It is preferable to set a three point bending load value of the first region 3a per deflection unit at 20 to 75 mN / mm. The length of the second flexible region 3b continuous with the first flexible region 3a is favorably set from 100 to 350 mm and especially favorably from 200 to 300 mm. It is preferable to set a three point bending load value of the second region 3b per deflection unit at 65 to 105 mN / mm. It is preferable to set the three-point bending load value of the second region 3b per unit deflection greater than that of the first flexible region 10 to 85 mN / mm. The length of the third flexible region 3c continuous with the second flexible region 3b is favorably set at 500 to 1500 mm and especially favorably at 800 to 1200 mm. It is preferable to set the value of the three-point bending load of the third region 3c per deflection unit from 95 to 320 mN / mm. It is preferable to set the three-point bending load value of the third region 3c per deflection unit greater than that of the second flexible region 3b from 30 to 250 mm.

An area of the inner tube 3 in the vicinity of an area thereof to be attached to the outer tube can be formed as an easily deformable area more deformable than other areas of the inner tube. The easily deformable area can be formed by not forming the body that imparts stiffness in only the area of the inner tube in the vicinity of the area thereof to be attached to the outer tube or by thinning only the area of the inner tube in the vicinity of the area. of the same to fix to the outer tube.

As the materials to be used to form the inner tube 3, materials having toughness and flexibility to some extent are preferable. It is possible to use polyolefin such as polyolefin and polypropylene; polyester such as polyamide or polyethylene terephthalate; fluorine-based polymer such as PTFE and ETFE; PEEK (polyetheretherketone); polyimide; synthetic resin elastomer such as olefinic elastomer (for example, polyethylene elastomer and polypropylene elastomer), polyamide elastomer, styrenic elastomer (for example, a styrene-butadiene-styrene copolymer, a styrene-isoprene-styrene copolymer, a styrene-isoprene-styrene copolymer -ethylene butylene-styrene); polyurethane, urethane-based elastomer, and fluorine-based elastomer; synthetic rubber such as urethane rubber, silicone rubber, and butadiene rubber; and natural rubbers such as latex rubber.

^{In the present disclosure, as shown in Figure} 8 ^{, the value of bending load of three points per unit of} deflection means a value of load measured when a load is applied to the center of a test specimen Y supported on a test table. support E between support points XX spaced a certain distance (L) by vertically moving a metal pressurizing rod Z (outer diameter: 1.5 mm) a certain distance. In the present invention, the distance between support points was set at 10mm. The test apparatus used was RTC-1210A (produced by Orientech Co., Ltd.). The vertical movement distance of the pressurizing rod was 2.0 mm. The test speed of the pressurizing rod was 5.0 mm / minute. Load values were recorded when the test sample was pressed by the 1.0 mm pressurizing rod. In the present invention, the bending load value of three points per unit deflection is used as an index simply to indicate the stiffness of the catheter.

The outer tube part 2 is a tubular body into which the inner tube 3 is inserted to such an extent that a leading end zone (proximal balloon zone) of the outer tube part is positioned in a zone (proximal of the front end of the inner tube a predetermined length) rearward from the front end of the inner tube 3 a predetermined length. A front end of the second lumen 12 communicates with a rear end of a front side sleeve area 21 which will be described later. A rear end of the second lumen 12 communicates with a second open area 55 of an injection port 53, provided in the branch connector 5, into which a balloon expansion fluid (eg, expansion liquid) is injected. balloon, specifically angiographic agent). It is favorable to set the outer diameter of the outer tube part 2 to 0.8 to 2.0 mm and especially favorable to set the outer diameter thereof to 0.8 to 1.0 mm. It is favorable to set the inner diameter of the outer tube part to 0.7 to 1.9 mm and especially favorable to set the inner diameter thereof to 0.7 to 0.8 mm.

In the balloon catheter 1 of this example, the outer tube portion 2 has the front side cuff area 21 and ^{an outer tube main body} 22 ^{extending from a rear end area of the front side sleeve area} 21 ^{to the proximal end of the balloon catheter} 1 ^{and is harder than the front side cuff area} 21. The outer tube main body 22 of the outer tube portion 2 may be provided with the stiffness-imparting body. As the rigidity-imparting body, the vane formed of the metal wire or the synthetic resin wire is preferable. In the balloon catheter 1 of this example, a bending load value of three points A1 per unit of deflection in an expandable zone P1 of the balloon part 4, a value of bending load of three points A2 per unit of deflection in the front side sleeve area 21 (P2), and a three point bending load value A3 per deflection unit in a front side area P3 of the outer tube main body 22 are set to A1 <A2 <A3 . The difference between the three-point bending load value A1 and the three-point bending load value A3 is set to no more than 300 mN / mm. The three point bending load value A1 is set to no more than 50 mN / mm.

The three point bending load value A1 is measured in an expandable zone 41 of the balloon part 4 in which the inner tube 3 does not have the marker. In the case where the marker is not provided in a central zone of the expandable zone 41, it is preferable to measure the three-point bending load value A1 in the central zone of the expandable zone. It is preferable to set the three-point bending load value A1 and a three-point bending load value A4 per deflection unit in a boundary zone 23 (P4) between the front side sleeve zone 21 and the main body. of outer tube 22 to A1 <A4, the difference between the value of bending load of three points A1 and the value of bending load of three points A4 to not more than 50 mN / mm, the value of bending load of three points A1 to no more than 50 mN / mm. Therefore, it is especially preferable to set the three point bending load values A1, A2, A3 and A4 to A1 <A2 <A4 <A3.

Therefore, the flexibility of the catheter balloon becomes steadily less from its front end to its rear end. In other words, the flexibility of the balloon becomes stepwise harder. Therefore, twisting hardly occurs on the front side (flexibility change region) of the balloon. Also since there is little difference in flexibility (hardness) on the front side (flexibility change region) of the balloon where there is a change in flexibility, the balloon is able to pass through a curved area of a blood vessel in large measure. Therefore, the balloon catheter of the present example can be inserted into lumens with a high degree of operability.

It is preferable to set the 3-point bending load value A1 of balloon catheter 1 to no more than 40 mN / mm. It is preferable to set the value of the three point bending load A2 to no more than 80 mN / mm. It is preferable to set the three point bending load value A3 to no more than 350 mN / mm and especially preferable to set it to no more than 130 mN / mm. It is preferable to set the A4 three point bending load value to no more than 120 mN / mm and especially preferable to set it to no more than 100 mN / mm. It is also preferable to set a three point bending load value A5 per deflection unit in a proximal area of the outer tube main body 22 greater than the three point bending load value A3 in a front end area of the outer tube main body. outer tube 22 and set the difference between the three-point bending load value A3 and the three-point bending load value A5 to no more than 450 mN / mm.

As shown in Fig. 5, the border area 23 arranged between the front side sleeve area 21 of ^{the outer tube part} 2 ^{and the outer tube main body} 22 ^{thereof has a lowering property that the hardness is reduced. gradually becomes larger from the proximal end of the front side sleeve area} 21 to the front end of the outer tube main body 22. More specifically, the border area 23 becomes ^{gradually thicker from the proximal end of the front side sleeve area} 21 ^{to the front end of the outer tube main body} 22 ^{with the inner diameter of the border area being substantially unchanged} and the outer diameter thereof becoming gradually thicker. The balloon catheter of the present example is not ^{limited to the way described above, but like a balloon catheter} 10 ^{of an embodiment shown in Figure} 6 ^{, it is possible to form the boundary zone 23 that gradually becomes thicker from the proximal end of the front side sleeve area} 21 ^{to the front end of the outer tube main body} 22 with ^the inner diameter of the boundary area gradually becoming smaller and the outer diameter thereof being substantially unchanged. Additionally, although it is preferable to provide the balloon catheter with the boundary zone, like a balloon catheter 20 of an embodiment shown in Figure 7, it is possible to form a balloon catheter, not having the boundary zone, in which All of the outer tube part 2 has almost the same property. In this ^{example, the front side sleeve area} 21 ^{and the outer tube main body} 22 ^{have the same property.}

The balloon part 4 has the expansion formation mode formed in advance and can be expanded by the balloon expansion liquid injected therein. More specifically, the balloon part 4 has the bulge area 40 which has the expansion formation mode formed by plastic deformation and a front side tubular zone 42, formed at a front side of the bulge area 40, which is less than the bulge zone 40 in diameter and thicker than bulge zone 40 and substantially non-expandable. The front side sleeve area 21 which is smaller than the bulge area 40 in diameter and thicker than the bulge area 40 and substantially non-expandable is disposed on a rear side of the bulge area 40. The bulge area 40 has a zone elastically deformable 41. The elastically deformable zone 41 can be stretched due to elastic deformation caused by internal pressure applied thereto. In the catheter of this embodiment, it is preferable to configure the balloon portion 4 to a diminished diameter mode having axially extending wrinkles 71. The bulge area 40 is thus formed so that it does not have circumferentially extending wrinkles.

The bulging area 40 of the balloon portion 4 is expanded by the liquid injected therein and elastically deforms beyond the forming mode, thus being able to closely contact the inner wall of a blood vessel. More specifically, the bulged area 40 is restored to a molded mode from the decreased diameter mode and thereafter is extensible (expandable). Thus, the bulging area safely contacts the inner wall of the blood vessel and does not damage the inner wall. In this example, bulge zone 40 is formed by stretching at temperatures not lower than its glass transition point and less than its softening point. The bulging area 40 expands without being subjected to resistance until before the end of the plastic deformation mode (molded mode) thereof. Thereafter the bulging area is expanded (stretched) by elastic deformation according to the pressure of the balloon expansion liquid injected thereto. After that, due to a decrease in pressure, the bulging area is restored to the mode before the bulging area is expanded by elastic deformation.

In the balloon catheter 1 of this example, the balloon part 4 has the bulge area 40 formed in the expansion-forming mode by plastic deformation. The bulged area 40 has the elastically deformable area 41, a front side tapering area 73, provided forwardly from the elastically deformable area 41, which tapers towards its front end in diameter and is substantially elastically non-deformable, and a tapering area. rear side 72, provided rearwardly from the elastically deformable zone, which decreases towards its rear end in its diameter and is substantially elastically non-deformable. The elastically deformable zone 41 is expandable in its diameter to such an extent that its diameter becomes larger than its diameter obtained when the elastically deformable zone is formed by molding the material. More specifically, it is favorable that without breaking, the elastically deformable zone is expandable not less than 2R compared to its outer diameter R that the deformable zone has elastically in the forming mode. It is more favorable than without breaking, the elastically deformable zone 41 is expandable not less than 2.5R compared to its outer diameter R which it has in the formation mode.

The thickness of the bulge area 40 is less than that of the front side tubular area 42 and that of the front side sleeve area 21. The front side tubular area 42 and the front side sleeve area 21 are not they stretch radially substantially. The bulging area 40 has the elastically deformable area 41, the front side tapering area 73, and the rear side tapering area 72. The front side tapering area 73 and the rear side tapering area 72 are formed as zones change in thickness gradually becoming thinner towards the elastically deformable zone 41. The front side tapering zone 73 and the rear side tapering zone 72 are substantially elastically undeformable.

As described later, it is preferable to form the bulge zone 40 due to the plastic deformation caused by internal pressure partially applied to the synthetic resin that is the material for the bulge zone at temperatures not lower than the glass transition point of the synthetic resin. and no greater than the softening point of the same. It is preferable to configure the bulged area 40 to the decreased diameter state where the diameter thereof becomes smaller than that of the plastic deformation mode of the bulged area formed by the plastic deformation. It is preferable to shape the bulged area to the state of reduced diameter by heat hardening. Thermal hardening is accomplished by heating and pressurizing using heat shrink tubing. By doing so, it is possible to safely configure the bulged area to the diminished diameter mode having the axially extending wrinkles 71. It is preferable to heat-harden the heat-shrinkable tube at a temperature in the vicinity of the softening point of the synthetic resin or a temperature below the softening point of the synthetic resin. softening it no more than 10 degrees. By doing so, it is possible to safely configure the bulge area to the diminished diameter mode having the axially extending wrinkles 71 without adversely affecting the plastic deformation of the bulge area.

The front side tubular area 42 is a short tubular area that extends almost an equal outside diameter and has a thickness greater than the bulge area 40. The front side sleeve area 21 extends almost an equal outside diameter and has a thickness greater than the bulging area 40. The front side tubular area 42 has an ^{outer diameter smaller than the front side sleeve area} 21 ^{and is attached to the front end area of the} inner tube 3. It is preferable to arrange the front of the front side tubular region 42 at a rear end of the imaging marker 32 or at a position near the rear end of the imaging marker. It is preferable that the front side tubular area 42 does not cover the imaging marker 32. It is preferable to fix the front side tubular area 42 to the inner tube 3 by heat sealing. The front side sleeve area 21 does not expand substantially when liquid is injected into it. ^{The front} side sleeve area 21 ^{forms a part of the balloon expansion lumen} 12 ^{between the inner surface thereof and the} outer surface of the inner tube 3.

As materials to be used to form the outer tube part 2 having the balloon part 4 integral therewith, thermoplastic synthetic resin is used which is elastically deformable when the thickness thereof is not greater than a predetermined thickness, it is elastically undeformable. when the thickness thereof is not less than the predetermined thickness, and it is flexible. More specifically, polyurethane elastomer and urethane elastomer, olefin elastomer (for example, polyethylene elastomer, polypropylene elastomer), polyester such as polyethylene terephthalate, soft polyvinyl chloride, polyamide elastomer, and amide elastomer are preferable. (eg, polyamide elastomer), fluororesin elastomer, and synthetic resin elastomer such as an ethylene vinyl acetate copolymer. Thermoplastic polyurethane elastomer (for example, thermoplastic aromatic polyurethane elastomer, thermoplastic aliphatic polyurethane elastomer) is especially preferable. Examples of the thermoplastic polyurethane elastomer include aromatic and aliphatic thermoplastic polyurethane elastomers. As materials to be used to form the outer tube part 2 having the balloon part 4 integral therewith, it is possible to use synthetic rubber such as urethane rubber, silicone rubber, and butadiene rubber; and natural rubbers such as latex rubber.

As materials to be used to form the outer tube part 2 having the balloon part 4 integral therewith, materials having a glass transition point of no greater than 0 degrees C are favorable and those having the point of Glass transition not greater than -10 degrees C. Materials that have a softening point (Vicat softening point) of not less than 70 degrees C are also favorable and those that have the softening point in a range from 80 degrees C are especially favorable. at 130 degrees C. The balloon part 4 has greater flexibility than the inner tube 3. In the balloon part 4, the outer diameter (outer diameter when the bulged area is restored to a molded manner) of the bulged area 40 is favorably set 0.9 to 2.1 mm and especially favorably 0.9 to 1.0 mm. The outer diameter (expandable outer diameter) of the bulging area is favorably set at 3.0 to 15.0 mm and especially favorably at 4.0 to 8.0 mm when the bulging area is expanded. The length of the bulging area 40 is favorably set at 3.5 to 14.5 mm and especially favorably at 4.0 to 5.5 mm. The degree of radial stretching of the bulging area is preferably set from 300 to 900. The degree of axial stretching of the bulging zone is preferably set from 200 to 350%.

The outer diameter of the front side tubular region 42 is favorably set at 0.6 to 1.9 mm and especially favorably at 0.7 to 0.9 mm. The length of the front side tubular region is favorably set at 1.0 to 3.0 mm and especially favorably at 1.5 to 2.5 mm. The outer diameter of the front side sleeve region 21 is favorably set to 0.9 to 2.1 mm and especially favorably to 0.9 to 1.0 mm. It is preferable to set the length B of the front side cuff area 21 to not less than 2.5 times the length A of the expandable area 41 of the balloon. It is especially preferable to set the length B of the front side sleeve area 21 to not less than three times and less than six times the length A of the expandable area 41. It is favorable to set the length B of the front side sleeve area 21 from 10 to 60 mm. It is more favorable to set the length B of the same from 15 to 45 mm and the most favorable to set the length B of the same from 20 to 30mm. The length A of the expandable zone 41 includes the length of the front side tapering zone 73 and that of the rear side tapering zone 72.

The bulge area 40 of the balloon part 4 is thinner than the front side tubular area 42 and the front side sleeve area 21. It is favorable to set the thickness of the bulge area 40 less than that of the sleeve area of front side 21 and that of the front side tubular area 42 from 0.03 to 0.18 mm and it is especially favorable to set the thickness thereof less than that of the front side sleeve area and the front side tubular area front 0.04 to 0.11 mm. It is favorable to set the thickness of the front side sleeve area 21 and that of the front side tubular area 42 from 0.07 to 0.20 mm and especially favorable to set the thickness thereof from 0.08 to 0.15 mm . In the catheter 1 of this example, the balloon part 4 is attached to the inner tube with the balloon part 4 axially stretched. Therefore, as shown in Fig. 2, the balloon part 4 is stretched axially a little. Thus there is a further decrease in the diameter of the bulging area configured in the decreased diameter mode.

It is favorable that the balloon catheter of the present example can be inserted into a guide catheter having an ^inner diameter of 1.1 ^{mm and especially favorable that it can be inserted into a guide catheter having an inner diameter} of 0.95 mm. . By forming the catheter that has this type of small diameter, it is possible to insert the catheter into lumens (in blood vessels) that have a small diameter. It is preferable that in the balloon catheter of the present invention, a guidewire having an outer diameter of 0.36mm can be inserted into the inner tube, and it is preferable that a guidewire having an outer diameter of 0.53mm can be inserted into the inner tube. By setting the inner diameter of the inner tube to such a extent, it is possible to use the guidewire which has a thickness to a certain extent and is capable of exhibiting sufficient guiding function and easy to insert the catheter into lumens (into blood vessels).

As shown in Figure 4, the branch connector 5 has an inner tube connector 52 that has the first open area 54 that communicates with the first lumen 11 and is attached to the rear end area of the inner tube 3 and a connector of outer tube 51 having the second open area 55 communicating with the second lumen 12 and forming the injection port 53 and attached to the rear end area of the outer tube portion 2. The outer tube connector 51 and the inner tube connector 52 are fixed together. The outer tube connector 51 and the inner tube connector 52 are fixed together by inserting the inner tube 3 into a rear end of the outer tube connector 51 mounted in the proximal region of the outer tube portion 2 from the front end of the inner tube 3 and join. The branch connector 5 is provided with a bending prevention tube 56 which covers the proximal area of the outer tube portion 2 and a leading end area of the branch connector 5. The injection port 53 is formed of a branch port 53a extended from a side wall of the outer tube connector 51, an injection port connector 53b, and a connecting tube 53c connecting the branch port 53a and the port port connector. injection 53b with each other. As materials to be used to form the branch connector, it is possible to suitably use thermoplastic resin such as polycarbonate, polyamide, polysulfone, polyarylate, and a methacrylate-butylene-styrene copolymer. As the connecting tube, a flexible synthetic resin or a soft synthetic resin is used.

The balloon catheter of the present invention is described below using embodiments shown in Figures 9 to 15. In the balloon catheter 100 shown in Figures 9 to 15, an outer tube portion is constructed of a ^{side cuff zone. front} 120 ^{and an outer tube main body} 102 ^{whose front end area is attached to} a rear end area of the front side cuff area 120. The balloon catheter 100 of this invention has an inner tube 103 having a first lumen 111 , the outer tube part that is provided coaxially with the inner tube 103, having its front end positioned rearwardly from the front end of the inner tube 103 a predetermined length, and forming a second lumen 112 between the outer tube part and an outer surface of the inner tube 103, and an expandable balloon part 104 whose front end zone 142 is fixed to the inner tube 103, whose rear end zone 144 is fixed to the inner tube outer tube, and whose interior communicates with the ^{second light} 112 ^.

The balloon portion 104 has an expansion formation mode formed in advance and can be expanded by a balloon expansion liquid injected therein. More specifically, the balloon portion 104 has a bulge area 140 having the expansion formation mode in which the bulge area is formed by plastic deformation and the front-side tubular area 142, formed on a front side of the bulge area. 140, which is smaller than the bulge area 140 in diameter and thicker than the bulge area and substantially non-expandable. A rear side of the bulge area 140 is the front side sleeve area 120 of the ^{substantially non-expandable outer tube portion and the front side sleeve area} 120 ^{is smaller in diameter than the} bulge area 140 and thicker than the bulge zone 140. bulge zone 140 has elastically deformable zone 141. elastically deformable zone 141 may extend due to elastic deformation caused by internal pressure applied to bulge zone 140. In the catheter of this invention, it is preferable to configure the balloon portion 104 to a decreased diameter mode having axially extending wrinkles 171.

In balloon catheter 100, a three-point bending load value A10 of an expandable zone of the balloon per unit of deflection and a three-point bending load value A20 of a fixed zone per unit of deflection where the end zone Rear of the front side sleeve area and the front end area of the outer tube main body are fixed to each other are set to A10 <A20. The difference between the A10 three-point bending load value and the A20 three-point bending load value is set to no more than 50 mN / mm. The A10 three-point bending load value is set to no more than 50 mN / mm. The three point bending load value A10 is measured in the expandable zone 141 of the balloon part 104 where the inner tube 103 does not have a marker. In the case where the marker is not arranged in a central area of the expandable area 141, it is preferable to measure the value of the three-point bending load A10 in the central area of the expandable area. In the present invention, the value of the three point bending load per unit deflection is measured using the method described above.

The balloon catheter 100 of this invention is formed of the outer tube portion, the inner tube 103, the bulge 140 and a branch connector 105. The inner tube 103 is a tubular body having the first lumen 111 whose leading end It's open. The first lumen 111 is used to insert a guide wire therein and inject a liquid medicine and the like into it. In the balloon catheter 100 of this embodiment, the first lumen 111 of the inner tube 103 communicates with a first open area 154 provided in the branch connector 105. It is favorable to set the outer diameter of the inner tube 103 to 0.6 to 1, 7 mm and especially favorable to set the outer diameter thereof at 0.6 to 0.7 mm. It is favorable to set the inner diameter of the inner tube to 0.4 to 1.4 mm and especially favorable to set the inner diameter thereof to 0.4 to 0.5 mm. Inner tube 103 is inserted into the outer tube part in such a way that a leading end region of the inner tube projects beyond the outer tube part. A second lumen 112 (balloon expansion lumen) is formed between the outer surface of the inner tube 103 and the inner surface of the outer tube portion and has a sufficiently large volume.

An imaging marker 132 is attached to the inner tube 103 at its leading end area (slightly proximal from a leading end 131 and in the vicinity of a leading end area 142 of the balloon portion 104). It is preferable to form the imaging marker from a radiopaque material (eg, gold, platinum, tungsten, alloys of these metals, or a silver-palladium alloy, a platinum-iridium alloy). In doing so, it is possible to check a leading end region of balloon catheter 100 by radiographic visualization. The inner tube 103 may be provided with a stiffness-imparting body 135. As a stiffness-imparting body, a vane formed of a metal wire or a synthetic resin wire is preferable. In the case where the inner tube 103 is provided with the stiffness-imparting body, it is preferable to arrange the stiffness-imparting body entirely on the inner tube except for its front end region, as shown in Fig. 11. More specifically, it is preferable to arrange the stiffness-imparting body in a range from the imaging marker 132 to the proximal end of the inner tube.

In the balloon catheter of this invention, as shown in Figure 9, the inner tube 103 has a first flexible region 3a arranged on the front side, a second flexible region 3b that is continuous with the first flexible region 3a and flexible but it has a greater hardness than the first flexible region 3a, and a flexible region 3c that is continuous with the second flexible region 3b and has a greater hardness than the second flexible region 3b. In this embodiment, as shown in Fig. 9, the first flexible region 3a which is the most flexible extends rearwardly from the front end of the inner tube 103 such that a rear end of the first flexible region 3a passes beyond of ^{a belt-shaped collapsed annular fastening area 106 disposed between the outer tube main body} 102 ^{described later and the front-side sleeve area} 120 ^{and is positioned rearwardly from the} collapsed annular fastening area in the form of strap a predetermined length. The length of the first flexible region 3a is favorably set at 100 to 350 mm and especially favorably at 200 to 300 mm.

It is preferable to set a three point bending load value of the first region 3a per deflection unit at 20 to 75 mN / mm. The length of the second flexible region 3b continuous with the first flexible region 3a is favorably set from 100 to 350 mm and especially favorably from 200 to 300 mm. It is preferable to set a three point bending load value of the second region 3b per deflection unit at 65 to 105 mN / mm. It is preferable to set the three-point bending load value of the second region 3b per unit deflection greater than that of the first flexible region 10 to 85 mN / mm. The length of the third flexible region 3c continuous with the second flexible region 3b is favorably set at 500 to 1500 mm and especially favorably at 800 to 1200 mm. It is preferable to set the value of the three-point bending load of the third region 3c per deflection unit from 95 to 320 mN / mm. It is preferable to set the three-point bending load value of the third region 3c per deflection unit greater than that of the second flexible region 3b from 30 to 250 mm. An area of the inner tube 103 in the vicinity of an area thereof attached to the outer tube can be formed as an easily deformable area more deformable than other areas of the inner tube. The easily deformable area having the manner described above can be formed by not forming the body that imparts stiffness over only the area of the inner tube in the vicinity of the area of the inner tube attached to the outer tube and by thinning only the area of the inner tube by the vicinity of the area of the same fixed to the outer tube.

The outer tube portion is a tubular body into which the inner tube 103 is inserted. A rear end of the second lumen 112 communicates with a second open area 155 of an injection port 153, provided in the branch connector 105 , into which a balloon expansion fluid (eg, balloon expansion fluid, specifically angiographic agent) is injected. The outer tube part is formed from the front side sleeve area 120 and the outer tube main body 102. It is favorable to set the outer diameter of the ^{outer tube} part from 0.8 ^to 2.0mm ^{and especially favorable to set the outer diameter thereof from} 0.8 ^to 1.0 ^mm. It is favorable to set the inner diameter of the outer tube part to 0.7 to 1.9 mm and especially favorable to set the inner diameter thereof to 0.7 to 0.8 mm. The front side sleeve area 120 of the outer tube portion does not expand substantially when liquid is injected into it. ^{The front side} sleeve area 21 ^{forms a part of the balloon expansion lumen} 12 ^{between the inner surface thereof and the} outer surface of the inner tube 103. By composing the front side of the outer tube portion of the area of ^{front side sleeve} 120 ^{axially extended by a predetermined length, the front side of the} outer tube part has greater flexibility than the main outer tube body 102. Thus the front side of the outer tube part is deformable, which enables to achieve a low profile (decrease in the outside diameter of the balloon catheter when inserted into a living body) and the balloon catheter is easily inserted into a lumen (eg, blood vessel) that has a small diameter.

The outer diameter of the front side sleeve region 120 is favorably set to 0.9 to 2.1 mm and especially favorably to 0.9 to 1.0 mm. The length of the front side sleeve region 120 is favorably set at 10 to 60 mm and especially favorably at 15 to 30 mm. It is preferable to form the ^{front end area of the outer tube main body} 102 ^{as an easily deformable front end area more} deformable than other areas of the outer tube main body. In this embodiment, the ^outer tube main body 102 ^{has a collapsed front end surface} 121 ^{that is oblique to the central axis} of the outer tube main body 102 at the front end area thereof. The front end of the front end surface dejected 121 is soft. Like the exemplary balloon catheter shown in Figures 21 and 22, it is possible to allow the ^{front end of the outer tube main body} 102 to ^{be flexible by forming the front end zone of the outer tube main body 102 as the thin front end zone or the} outer tube body 102. ^{form a slit in the} front end zone thereof.

As the materials to be used to form the outer tube main body 102 and the inner tube 103, materials having toughness and flexibility to a certain extent are preferable. It is possible to use polyolefin such as polyolefin and polypropylene; polyester such as polyamide or polyethylene terephthalate; fluorine-based polymer such as PTFE and ETFE; PEEK (polyetheretherketone); polyimide; synthetic resin elastomer such as olefinic elastomer (eg, polyethylene elastomer and polypropylene elastomer), polyamide elastomer, styrenic elastomer (eg, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, copolymer styrene-ethylene butylene-styrene); polyurethane, urethane-based elastomer, and fluorine-based elastomer; synthetic rubber such as urethane rubber, silicone rubber, and butadiene rubber; and natural rubbers such as latex rubber. The outer tube main body 102 may be provided with a stiffening-imparting body. As the rigidity-imparting body, a vane formed of a metal wire or a synthetic resin wire is preferable.

The expandable zone 141 of the balloon portion 104 is expanded by a liquid injected therein and capable of closely contacting the interior wall of a blood vessel. More specifically, the expandable zone 141 is restored to a molded mode from a decreased diameter mode configured by the balloon expansion liquid injected therein and thereafter extensible (expandable). Thus, the expandable zone safely contacts the inner wall of the blood vessel and does not damage the inner wall. In this invention, expandable zone 141 is formed by stretching a material at temperatures not less than its glass transition point and less than its softening point. The expandable zone expands without being subjected to resistance until before the end of the plastic deformation mode (molded mode) thereof. Thereafter the bulging area is expanded (stretched) by elastic deformation according to the pressure of the balloon expansion liquid injected thereto. After that, due to a decrease in pressure, the bulging area is restored to the mode before the bulging area is expanded by elastic deformation.

The thickness of the expandable area 141 is less than that of the front side tubular area 142 and that of the front side sleeve area 120 of the outer tube portion. The front side tubular area 142 and the front side sleeve area 120 are not substantially radially stretched. A front side area 173 of the expandable area 141 and a rear side area 172 thereof are formed as thickness change areas that gradually become thinner towards the expandable area 41. It is preferable to configure the front side area 173 of the expandable area 141 and the rear side area 172 thereof to a mode in which the front side area and the rear side area fall towards an inner side of the expandable area 141. By doing so, it is possible to prevent a raised area of the expandable zone 141 constitutes an obstacle when the balloon catheter is progressing into the blood vessel, when the balloon catheter is inserted into a guide catheter, and when the balloon catheter is accommodated in a container. Thus, a catheter insertion operation can be favorably performed.

As described later, it is preferable to form the expandable zone 141 due to the plastic deformation caused by internal pressure partially applied to the synthetic resin which is the material used to form the expandable zone at temperatures not lower than the glass transition point of the synthetic resin and no greater than its softening point. It is preferable to configure the expandable zone 141 to the decreased diameter state where the diameter thereof becomes smaller than that of the expandable zone having the expansion formation mode formed by plastic deformation. It is preferable to configure the expandable zone to the state of reduced diameter by heat hardening. Thermal hardening is accomplished by heating and pressurizing using heat shrink tubing. By doing so, it is possible to safely configure the expandable zone 141 to the diminished diameter mode having the axially extending wrinkles 171. It is preferable to heat harden the heat shrinkable tube at a temperature in the vicinity of the softening point of the synthetic resin or a temperature lower than the softening point of the synthetic resin not more than 10 degrees. By doing so, it is possible to safely configure the expandable zone to the diminished diameter mode having the axially extending wrinkles without adversely affecting the plastic deformation of the expandable zone.

The front-side tubular area 142 is a short tubular area that extends nearly an equal outside diameter and has a thickness greater than the expandable area 141. The front-side sleeve area 120 of the outer tube portion extends in nearly equal outside diameter and is axially longer than front side tubular area 142 and is thicker than expandable area 141. Front side tubular area 142 has a smaller outside diameter than front side sleeve area 120 and is attached to the front end area of the inner tube 103. It is preferable to arrange the front of the front side tubular area 142 at a rear end of the imaging marker 132 or at a position near the rear end of the imaging marker . It is preferable that the front side tubular area 42 does not cover the imaging marker 132. It is preferable to fix the front side tubular area 142 to the inner tube 103 by heat sealing.

As materials to be used to form the balloon part 104 and the front side sleeve area 120, thermoplastic synthetic resin having elasticity is used. More specifically, polyurethane elastomer and urethane elastomer, olefin elastomer (for example, polyethylene elastomer, polypropylene elastomer), polyester such as polyethylene terephthalate, soft polyvinyl chloride, polyamide elastomer, and amide elastomer are preferable. (eg, polyamide elastomer), fluororesin elastomer, and synthetic resin elastomer such as an ethylene vinyl acetate copolymer. Thermoplastic polyurethane elastomer (for example, thermoplastic aromatic polyurethane elastomer, thermoplastic aliphatic polyurethane elastomer) is especially preferable. Examples of the thermoplastic polyurethane elastomer include aromatic and aliphatic thermoplastic polyurethane elastomers.

As materials to be used to form the balloon part 104 and the front side sleeve area 120, materials having a glass transition point of no more than 0 degrees C are favorable and those having the glass transition point of no more than 0 degrees C are especially favorable. greater than -10 degrees C. Materials having a softening point (Vicat softening point) of not less than 70 degrees C are favorable and those having a softening point in a range from 80 degrees C to 130 degrees C are especially favorable. The balloon portion 104 having greater flexibility than the inner tube 103 and the front side sleeve area 120 is preferable. In the balloon portion 104 of this embodiment, an end area of the front side tubular area 142 in a expandable zone side thereof and an end zone 174 of the front side sleeve zone 120 on the expandable zone side thereof have a small diameter respectively. It is preferable to set the length of the ^{front side sleeve} area 120 ^{greater than the axial length of the front side tubular area and extends the} front side sleeve area backward. By doing so, the total length of the balloon is allowed to be long. Thus it is possible to form a long low profile area in the front side area of the catheter.

As shown in Figures 10 and 11, the front side sleeve area 120 has a non-expandable tubular area (in other words, sleeve area) extending a predetermined length toward the rear end of the outer tube portion. The front side sleeve area 120 has a lowered rear end surface 145 oblique to the central axis of the tubular area. The front side sleeve area 120 of the outer tube portion and ^{the front end area of the outer tube main body} 102 ^{described later are folded down to the central axis of the outer tube main body} 102 ^{and are fixed to each other in the annular fastening zone folded down in the form of a strap 106} formed airtight.

In the balloon part 104, the outer diameter (outer diameter when the expandable zone is restored to molding) of the expandable zone 141 is favorably set to 0.9 to 2.1 mm and especially favorably to 0.9 to 1, 0 mm. When the expandable zone is expanded, its outer diameter (expandable outer diameter) is favorably set at 3.0 to 15.0 mm and especially favorably at 4.0 to 8.0 mm. The length of the expandable zone 141 is favorably set at 3.5 to 14.5 mm and especially favorably at 4.0 to 5.5 mm. The degree of stretching of the expandable zone in its radial direction is preferably set from 300 to 900%. The degree of stretching of the expandable zone in its axial direction is preferably set from 200 to 350%. The outer diameter of the front side tubular region 142 is favorably set at 0.6 to 1.9 mm and especially favorably at 0.7 to 0.9 mm. The length of the front side tubular region is favorably set at 1.0 to 3.0 mm and especially favorably at 1.5 to 2.5 mm.

The expandable area 141 of the balloon part 104 is thinner than the front side tubular area 142 and the front side sleeve area 120. It is favorable to set the thickness of the expandable area 141 less than that of the tube sleeve area. front side 120 and that of the front side tubular area 142 from 0.03 to 0.18 mm and it is especially favorable to set the thickness thereof less than that of the front side sleeve area and the front side tubular area 0.04 to 0.11 mm. It is favorable to set the thickness of the front side sleeve area 120 and that of the front side tubular area 142 from 0.07 to 0.20 mm and especially favorable to set the thickness of the front side sleeve area and that of the front side. the front side tubular zone from 0.08 to 0.15 mm. In catheter 100 of this invention, balloon portion 104 is attached to a stem region with balloon portion 104 axially stretched. Therefore, as shown in Figures 10 and 11, the balloon portion 104 is axially stretched somewhat. Thus there is a further decrease in the diameter of the expandable zone configured in the decreased diameter mode.

In the balloon catheter 100 of the present invention, the three-point bending load value A10 of the expandable zone (P10 in Figures 10 and 11, in this example, the central zone of the expandable zone where the marker) of the balloon per unit of deflection and the three-point bending load value A20 of the fixed zone (P20 in Figures 10 and 11) per unit of deflection where the rear end zone of the front side cuff zone and The front end zone of the outer tube main body are fixed to each other are set to A10 <A20. The difference between the three-point bending load value A10 (P10 in Figures 10 and 11) and the ^{three-point bending load} value A 20 ^(P 20 ^{in Figures} 10 ^and 11 ^{) is set to no more than 50 mN / mm. As} described above, in the balloon catheter of the present invention, the three-point bending load value A20 is greater than the three-point bending load value A10, and the difference between the bending load value A10 three-point bending load and A20 three-point bending load value is set to no more than 50 mN / mm. Therefore, in the front side region of the catheter from the front end thereof to the fixation zone where the front side sleeve zone and the outer tube main body are fixed to each other, the flexibility of the catheter region front side becomes smaller in a staggered manner from its front end to its rear end. In other words, the flexibility of the front side region becomes steadily harder. Therefore, kinking hardly occurs in the leading end zone (flexibility change region) of the catheter. Also since there is little difference in flexibility (hardness) on the front side (flexibility change region) of the catheter where there is a change in flexibility, the catheter is capable of passing through a curved area of a blood vessel in large measure. Therefore, the balloon catheter of the present invention can be inserted into lumens with a high degree of operability.

It is preferable to set the three point bending load value A10 (P10 of Figures 10 and 11) to no more than 50 mN / mm. It is especially preferable to set the A10 three point bending load value to no more than 50 mN / mm. It is preferable to set the three-point bending load value A20 (P20 of Figures 10 and 11) to no more than 100 mN / mm. It is preferable to set the three-point bending load value of the front side sleeve area 120 of the outer tube portion positioned between P10 of Figures 10 and 11 and P20 of Figures 10 and 11 ^{greater than the load value three-point} bending load A 10 ^{and less than the three-point bending load value A30.} In the balloon catheter, where the three-point bending load values are set as described above, kink hardly occurs to a lesser extent, and the catheter has high performance when passing through the blood vessel.

It is preferable to set the three-point bending load value A30 (P30 of Figures 10 and 11) per ^{deflection unit in an area of the outer tube main body} 102 ^{disposed on the proximal side from the fixation area} 106 of the main body. of outer tube 102 greater than the three point bending load value A20 (P20 of Figures 10 and 11). It is preferable to set the difference between the A30 three-point bending load value (P30 of Figures 10 and 11) and the A20 three-point bending load value (P20 of Figures 10 and 11) to no more than 300 mN / mm. In the balloon catheter where the three-point bending load values are set as described above, in the front side region of the catheter from the front end thereof to the front end area of the outer tube main body, the flexibility becomes less staggered from the front area to rear sides of the front side region. In other words, the flexibility of the front side region becomes stepwise harder from the front to the rear sides thereof. Therefore, twisting hardly occurs in the front side region including the front end area of the outer tube main body. Furthermore, since the area of the proximal catheter from the attachment area 106 ^{of the outer tube} main body 102 ^{is hard to some extent, the transmissivity of a pressing force applied to the proximal end of} the catheter is favorable.

It is preferable to set the A30 three point bending load value (P30 of Figures 10 and 11) to no more than 350 mN / mm. It is preferable to set the difference between the A20 and A30 three-point bending load values to no more than 300 mN / mm. It is favorable that the balloon catheter of the present invention can be inserted into a ^{guide catheter having an inner diameter of} 1.1 ^{mm and especially favorable that it can be inserted into a guide catheter} having an inner diameter of 0.95 mm. In the balloon catheter 100 of the present invention, the three-point bending load value A20 is greater than the three-point bending load value A10, and the difference between the three-point bending load values A10 and A20 is set to no more than 50 mN / mm. Therefore, the balloon catheter of the present invention has a high degree of insertion operability, although it has a small diameter. By forming the catheter that has this type of small diameter, it is possible to insert the catheter into lumens (in blood vessels) that have a small diameter. In the balloon catheter of the present invention, it is preferable that a guidewire having an outer diameter of 0.36mm can be inserted into the inner tube, and it is especially preferable that a guidewire having an outer diameter of 0.53 mm can be inserted into the inner tube. By setting the inner diameter of the inner tube to such an extent, it is possible to use the guidewire which has a thickness to a certain extent and is capable of exhibiting sufficient guide function. That way it is easy to insert the catheter into lumens (into blood vessels).

In the balloon catheter of this invention, a fixation zone 106 in which the trailing end of the ^{front side} cuff area 120 ^{and the front end area of the outer tube main body} 102 ^{are joined together is formed} as a bonding area. folded ring fixation (in other words, folded ring fixation zone). The three-point bending load value A20 (P20 of Figures 10 and 11) indicates the hardness of the collapsed annular fixing zone. In other words, the three-point bending load value A20 indicates a measured load value when a load is applied vertically to the central zone of the annular clamping zone with a pressurizing rod. Using Figures 13 and 15, ^{the attachment zone 106 is described below in which the front side cuff zone} 120 ^{of the balloon catheter of this embodiment and the front end zone of the outer tube main body} 102 ^{are joined together. .}

As described above, the outer tube main body 102 has the ^folded forward end surface 121 ^{oblique to the central axis of the outer tube main body} 102 ^{at the front end area thereof.} The balloon portion 104 has the rear end surface collapsed 145 to the center axis of the front side sleeve area 120 at the rear end area 144 thereof. A front end area of the ^{outer tube} main body 102 ^{and a rear end area of the front side sleeve area} 120 ^{axially overlap} each other. The balloon catheter has the airtight ^{strap-shaped collapsed annular fixation area 106 disposed in the area where the front end area of the outer tube main body} 102 ^{and the rear end area of the front side sleeve area} 120 ^{overlap each other and collapse to the central axis} of the outer tube main body 102. The outer tube main body 102 and the balloon part 104 are fixed to each other in the collapsed annular fixing area 106. As the sleeve area of front side 120 of the outer tube part is ^{more flexible than the front end area of the outer tube main body} 102 ^{, the area where the} collapsed annular fixing area 106 is formed becomes higher in flexibility thereof from its rear end to its front end. Therefore, in the vicinity of the front end zone of the outer tube main body 102, a change point is not formed where the property changes abruptly. This prevents the vicinity of the ^{leading end region of the outer tube main body} 102 from ^{kinking and having a} preferable deformability.

In the balloon catheter 100 of this invention, the rear end of the front side cuff region 120 is it forms as an increased diameter area (in other words, collapsed increased diameter area, collapsed expandable area). The rear end surface 145 of the front side sleeve area 120 forms the collapsed ^{rear end surface, collapsed at a predetermined angle, to the central axis of the front side sleeve area} 120 (outer tube main body 102). The front end area of the outer tube main body 102 enters the rear end area of increased diameter 144. The inlet area forms the area where the ^{front end area of the outer tube main body 102 and the rear end area} of the outer tube body 102. ^{front side sleeve} 120 overlap each other. The outer diameter of the outer tube main body 102 is almost equal to that of the front side sleeve area 120 of the outer tube portion. The rear end of the ^front side sleeve area 120 ^{is in a bulged state.}

In the balloon catheter 100 of this invention, as shown in FIG. 14, the collapsed rear end surface 145 of the front side cuff area 120 and the collapsed front end surface 121 ^{of the outer tube} main body 102 ^{are nearly parallel to each other or the difference between the collapse angle of the collapsed} rear end surface of the front side sleeve area that forms with the central axis of the outer tube and the collapse angle of the collapsed front end surface of the main body of The outer tube that forms with the central axis of the outer tube is set at no more than 44 degrees and preferably no more than 20 degrees. As the balloon catheter shown in Fig. 14, it is preferable to set a fold angle D of the ^{lowered front} end surface 121 ^{of the outer tube main body} 102 ^{which forms with the central axis of} the outer tube main body 102 greater than a tilt angle C of the collapsed rear end surface 145 of the ^{front side sleeve} area 120 ^{(outer tube main body} 102 ^{) which forms with the central axis of the} front side sleeve area 120 (outer tube main body 102 ). It is preferable to set the folding angle C of the lowered rear end surface 145 of the front side sleeve area 120 which forms with the central axis of the front side sleeve area 120 (outer tube main body 102) from 20 to 30 degrees and especially favorably from 22 to 28 degrees. It is preferable to set the folding angle D of the ^{lowered front end surface} 121 ^{of the outer tube main body} 102 ^{which forms with the central axis} of the outer tube main body 102 at 30 to 45 degrees and especially favorably at 35 to 43 degrees.

The front end area of the outer tube main body 102 which has been inserted into the rear end area of increased diameter 144 of the front side sleeve area 120 is airtight attached to the balloon portion 104 and forms the attachment area. annular collapsed strap-like area 106. Annular collapsed attachment area 106 has an annular firm attachment area 161. Attachment area 161 is formed over the entire inner surface of proximal area 144 of front-side sleeve area 120 contacting the outer surface of the front end zone of the outer tube main body 102 of the folded annular firm fixation zone 106. As described later, a non-fixation zone can be provided that does not adversely affect the air tightness. air between both surfaces. It is preferable that the annular firm fixation zone 161 is almost uniform or gradually becomes larger towards its rear end in its width. In the balloon catheter 100 of this embodiment, as shown in FIG. 14, the annular secure fixation zone 161 gradually becomes larger towards its rear end in its width.

In the balloon catheter 100 of this invention shown in Figure 14, an imaginary line connecting a ^front end 122 ^{of the front end surface downcast} 121 ^{of the main body of} the ^{outer tube} 102 ^{and a} front ^end 146 of the rear end surface downcast 145 of the front side sleeve region 120 is nearly parallel to the central axis of the outer tube main body 102. That is, the front end 122 of the ^{collapsed front end} surface 121 ^{of the outer tube main body} 102 ^{is positioned forward. from the} front end 146 of the collapsed rear end surface 145 of the front side sleeve area 120. Similarly an imaginary line connecting a rear end 123 of the collapsed front end surface 121 of the outer tube main body 102 and a rear end 147 of the collapsed rear end surface 145 of the front side sleeve area 120 is almost parallel to the central axis of the outer tube main body 102. That is, the rear end 123 of the collapsed front end surface 121 of the outer tube main body 102 is positioned forward from the rear end 147 of the collapsed rear end surface 145 of the front side sleeve 120. Therefore, a small area in width is not formed in the annular firm fixation area 161.

In this invention, the forward end 146 of the collapsed rear end surface 145 of the front side sleeve area 120 is positioned forward from the front end 123 of the collapsed front end surface 121 of the outer tube main body 102. By therefore, the property of the collapsed annular fixing zone 106 changes continuously. Since the front side sleeve area 120 of the outer tube portion has greater ^{flexibility than the front end area of the outer tube main body} 102 ^{, the area where the} collapsed annular fixing area 106 is formed gradually becomes higher from its rear end to its front end in its flexibility. In the collapsed annular fixing area 106 of this embodiment, an area where the rear end area 144 of the front side sleeve area 120 covers the front end area of the outer tube main body 102 ^{increases from the rear end of the front side sleeve area. annular collapsed attachment 106 to the front end thereof.} When the rear end 144 of the front side sleeve area 120 passes the rear end 123 of the ^{collapsed front end surface} 121 ^{, the rear end of the front side sleeve area} 120 ^{continues to} increase in the sectional area of a section. of the same orthogonal to the central axis of the main body of outer tube. But the front end zone of the outer tube main body 102 decreases in sectional area of a section thereof orthogonal to the central axis of the outer tube main body. The extreme zone section rear 144 of the front side sleeve area 120 becomes annular at the front end 146 of the collapsed surface 145 provided at the rear end of the front side sleeve area 120. On the front side of the front end 146, the area The front end of the outer tube main body 102 decreases in sectional area thereof and ends at the front end 122. That is, the entire collapsed annular fixation area 106 ^{of the balloon catheter of this invention, nor the rear end area of The front side sleeve area} 120 ^{nor the front end area of the outer tube main body} 102 ^{has an annular area on a cut orthogonal surface to the central axis of the outer tube main body} 102 ^.

It is preferable to set a distance O between the front end 122 of the outer tube main body 102 shown in FIG. 14 and the front end 146 of the lowered rear end surface 145 of the front side sleeve area 120 from 0.5 to 2 , 0 mm and especially preferable to set the distance O to 0.6 to 1.5 mm. It is preferable to set a distance N between the rear end 123 of the lowered front end surface 121 of the outer tube main body 102 and the rear end 147 of the lowered rear end surface 145 of the front side sleeve area 120 of 0, 5 to 4.0 mm and especially it is preferable to set the distance N to 0.6 to 1.0 mm. It is preferable to set an axial length L (in other words, the distance L between the front end 122 of the outer tube main body 102 and the rear end 147 of the lowered rear end surface 145 of the front side sleeve area 120) of 2.0 to 8.0 mm and especially preferable to set the distance L to 2.3 to 3.5 mm. It is preferable to set a distance M between the rear end 123 of the lowered front end surface 121 of the outer tube main body 102 and the front end 146 of the lowered rear end surface 145 of the front side sleeve area 120 of 0, 6 to 2.5 mm and especially preferable to set the distance N to 0.8 to 1.5 mm. The distance M between the rear end 123 of the lowered front end surface 121 of the outer tube main body 102 and the front end 146 of the lowered rear end surface 145 of the front side sleeve area 120 can be set to zero. That is, as an embodiment shown in FIG. 15, the rear end 123 of the collapsed front end surface 121 of the outer tube main body 102 and the front end 146 of the collapsed rear end surface 145 of the ^{side sleeve area. front} 120 ^{may be coincident with each other in the axial direction of} the outer tube main body 102. It is preferable that the rear end 123 of the lowered front end surface 121 of the outer tube main body 102 is not located on a front side of the end. front 146 of the folded rear end surface 145 of the front side sleeve area 120.

As shown in Fig. 15, the collapsed annular clamp area 106 is formed by inserting the front end area ^{of the outer tube main body} 102 ^{into the rear end of the front side sleeve area} 120 ^{, which} fits into a shrink tube. by heat on an overlapped area and on the front and rear areas of the ^{overlapped area by a length of about 2mm, and heating the outer surface of the heat shrinkable tube by} using a heating member 7 to fuse the two together. The outer edge of the collapsed front end surface of the outer tube main body 102 is edgeless and rounded due to melting. As shown in FIG. 15, the fusing process can be performed in such a way that the leading end region of the collapsed leading end surface 121 of the outer tube main body 102 is not directly heated. By doing so, at the front end of the outer tube main body 102, it is possible to form a non-melting zone 176 that does not melt to the rear end of the front-side sleeve zone 120 or forms a weak melt zone. By forming this type of weak melt zone, the rear end of a zone (non-overlapping zone) of the ^front side sleeve zone 120 ^{where the outer tube main body} 102 ^{is not present is not compressed by the} heat shrink tube. heated. This prevents a thin area from forming in a sealing area.

The way of joining the rear end of the front side sleeve area 120 and the front end area ^{of the outer tube main body} 102 to ^{each other is not limited to that described above, but may be of a type such as} a balloon catheter has. 110 of another exemplary balloon catheter shown in Figures 16 and 17. In the balloon catheter 110 ^{of this example, the leading end region of the outer tube main body} 102 ^{is formed as a} collapsed small diameter region 125. The end surface collapsed front end 121 is formed at a forward end of the collapsed small diameter area. The outer diameter of the rear end of the ^front side sleeve area 120 ^{is nearly equal to that of an area of the outer tube main body disposed proximally of the} collapsed small diameter area of the outer tube main body 102. An annular fastening area collapsed area 106a is ^{formed by inserting the collapsed small diameter area of the outer tube main body} 102 ^{into the collapsed} rear end area 144 of the front side sleeve area 120 and fixing the collapsed small diameter area to the collapsed rear end area 144 In the balloon catheter 110, a part of the rear end area of the front side cuff area 120 is formed as a collapsed expandable area. A portion of the ^front side sleeve area 120 ^{rearwardly from the collapsed expandable area extends to the rear end area} of the outer tube main body 102 by nearly equal outer diameter. The way of joining the rear end of the ^{front side} sleeve area 120 ^{and the front end area of the outer tube main body} 102 to ^{each other may be of a type such} as has a balloon catheter 130 of the example shown in Figures 18 and 19.

In the balloon catheter 130 of this example, the trailing end of the front side cuff area 120 is formed not as the collapsed enlarged diameter area, but as an obliquely terminated area formed by extending the front side cuff area backward. . The front end area of the outer tube main body 102 has the collapsed small diameter area 125 and a thick area 124 continuous therewith. The collapsed leading end surface 121 is formed at the leading end of the collapsed small diameter area 125. The ^{outer diameter of a portion of the outer tube main body} 102 ^{disposed proximally of the diameter area small folded down thereof is established almost the same as that of the front side sleeve area} 120 ^{and that of the} rear end area thereof. A collapsed annular attachment region 106b is formed by inserting the collapsed small diameter area 125 of the outer tube main body 102 into the collapsed rear end area of the front side sleeve area 120 and attaching thereto. In balloon catheter 130, a portion of the front side sleeve area 120 disposed rearwardly from the expandable area 141 extends to the rear end area of the outer tube main body 102 by almost a uniform outer diameter. The balloon catheter 130 is thus constructed so as not to have a different level zone in a zone where the balloon portion 104 exposed to the outside and the outer tube main body 102 are joined together. Like a balloon catheter 150 shown in FIG. 20, the ^{outer tube main} body 102 ^{can be extended to the rear end zone of the balloon catheter by an} inside diameter entirely equal to that of the collapsed small diameter zone 125. A zone of Annular collapsed attachment 106c ^{is formed by inserting the collapsed front end area of the outer tube main body} 102 ^{into the collapsed rear end area of the front side sleeve area} 120 ^{and attaching thereto.}

The way of joining the rear end of the front side sleeve area 120 and the front end area ^{of the outer tube main body} 102 to ^{each other is not limited to those described above, but may be of a} balloon catheter type. 160 of yet another exemplary balloon catheter shown in Figure 21 has. In the ^{balloon catheter 160 of this example, the front end area of the outer tube main body} 102 ^{is formed not as the} collapsed area of the embodiment described above, but as a thin small diameter area 127. The front end area of the outer tube of this example is also formed as the easily deformable leading end zone more deformable than other zones of the outer tube. The inner diameter of the rear end of the front side sleeve area 120 is nearly equal to the outer diameter of the thin small diameter area 127 of the outer tube main body 102. A collapsed annular locking area 106f is formed by inserting the area collapsed small diameter 127 of the outer tube main body 102 at the rear end of the front side sleeve area 120 and attached thereto. In the balloon catheter 160, the rear side area of the front side cuff area 120 is formed as the increased diameter area and covers the thin small diameter area 127 of the outer tube main body 102. The outer diameter of the tube Trailing end of the front side sleeve area 120 ^{is nearly equal to that of an area of the outer tube main body} 102 ^{disposed rearwardly from the} thin small diameter area 127 thereof. The balloon catheter 160 is so constructed not to have an area of ^different level ^{and a clearance in an area where the rear end zone sleeve front side} 120 ^{exposed to the outside and the main body outer tube} 102 ^{are joined each.}

The way of joining the rear end of the front side sleeve area 120 and the front end area of the outer tube main body 102 to each other may be as a balloon catheter 170 has a type of yet another exemplary balloon catheter shown in Figure 22. In the balloon catheter 170 of this example, as with the ^{balloon catheter 160, the front end zone of the outer tube main body} 102 ^{is formed not like the collapsed zone} of the embodiment described above, but like the zone thin small diameter 127. The leading end area of the outer tube of this example is also formed as the easily deformable leading end area more deformable than other areas of the outer tube. Unlike balloon catheter 160, the trailing end of front side cuff area 120 is not shaped like the increased diameter area. Thus the ^{front side} sleeve area 120 ^{of the outer tube portion extends entirely over a nearly uniform inner diameter and a} uniform outer diameter. The outer diameter of the thin small diameter area 127 in the ^{front end area of the outer tube main body} 102 ^{is almost equal to the inner diameter of the} front side sleeve area 120 of the outer tube portion. A collapsed annular attachment area 106g is formed by inserting the thin small diameter area 127 of the outer tube main body 102 into the rear end of the front side sleeve area 120 and attaching thereto. The balloon catheter 170 is thus constructed so as not to have a different level zone in a zone where the balloon portion 104 exposed to the outside and the outer tube main body 102 are joined together.

As shown in FIG. 12, the branch connector 105 has an inner tube connector 152 that has a first open area 154 that communicates with the first lumen 111 and attaches to the rear end area of the inner tube 103 and an inner tube connector. outer tube 151 having a second open area 155 communicating with the second lumen 112 and forming an injection port 153 and attached to the rear end area of the outer tube main body 102. The outer tube connector 151 and the inner tube connector 152 are fixed together. The outer tube connector 151 and the inner tube connector 52 are secured together by inserting the inner tube 103 into a rear end of the outer tube connector 151 mounted in the proximal area of the outer tube main body 102 from the forward end of the inner tube 103 and join. The branch connector 105 is provided with a bending prevention tube 156 that covers the proximal area of the outer tube main body 102 and a leading end area of the branch connector 105. The injection port 153 is formed of a branch access port 153a extended from a side wall of the outer tube connector 151, an injection port connector 153b, and a connecting tube 153c connecting the branch port 153a and the port port connector. injection 153b with each other. As materials to be used to form the branch connector, it is possible to suitably use thermoplastic resin such as polycarbonate, polyamide, polysulfone, polyarylate, and a methacrylate-butylene-styrene copolymer. As the connecting tube, a flexible synthetic resin or a soft synthetic resin is used.

The construction of the balloon catheter is not limited to those described above, but the balloon catheter may have a guidewire insertion opening that communicates with a guidewire lumen in an intermediate zone. (backwards from the folded annular fixing zone 106) thereof. It is preferable to apply the balloon catheter of the present invention to a medicine delivery catheter provided with a blood vessel occlusion function.

Industrial applicability

The balloon catheter of the present invention has the features defined in claim 1. The balloon part has the expansion formation mode formed in advance. Even before the expansion-forming mode is formed, the balloon part is expanded by a very low pressure of the liquid injected therein and is capable of elastically deforming beyond the expansion-forming mode. Thereby the balloon part closely contacts the inner wall of a blood vessel and is able to occlude the blood vessel. Additionally, since the outer tube part has the front side cuff zone integrally formed with the ^{balloon part, the catheter does not have a sharp change in property in the region (front side region) from the} front end of the catheter to The front side cuff area of the outer tube has little kink generation in the front side region thereof, and favorably passes through a curved area of the blood vessel. The bulge portion is elastically deformable, while the front side sleeve area is substantially non-expandable. Thus when the balloon expands, the diameter of the front side cuff area does not increase. Therefore, the operability of the catheter is not impaired.

Claims (1)

1. A balloon catheter (1, 10, 100, 110, 130, 160, 170) comprising an inner tube (3, 103) having a ^{first lumen (} 11 ^, 111 ^); an outer tube part (2) provided coaxially with said inner tube (3, 103) and forming a second ^{lumen (12,} 112 ^{) between said outer tube part (} 2 ^{) and an outer surface of said inner tube (3, 103);} and a balloon part (4, 104), a front end zone of which is fixed to a front end zone of said inner tube (3, 103) and an interior of which communicates with said second lumen (12, 112) , said balloon part (4, 104) has a bulging area (40, 140), which has an expansion formation mode formed in advance, which is elastically deformable beyond said expansion formation mode by an expansion liquid of balloon injected inside it, ^{said outer tube part (} 2 ^{) has a front side sleeve area (} 21 ^, 120 ^{) extending from a} rear end area of said bulging area (40, 140) of said balloon part (4, 104) towards a proximal end of said outer tube part, is integrally formed with said balloon part (4, 104) by using the same material as that to be used for said balloon part (4, 104), and is substantially non-expandable , characterized by ^{said outer tube part (} 2 ^{) has an outer tube main body (} 22 ^, 102 ^{) having a front end zone attached to a rear end zone of said front side sleeve zone (} 21 ^, 120 ^), said front side sleeve area (21, 120) has a lowered rear end surface (145) oblique to said central axis of the tubular area (42, 142), ^{said outer tube main body (} 22 ^, 102 ^{) has a collapsed front end surface (} 121 ^{) oblique to said} central axis of said outer tube main body, ^{said outer tube portion (} 2 ^{) has a belt-shaped collapsed annular attachment area (106) formed by attaching an overlapping area of said rear end area of said front side sleeve area (} 21 ^, 120 ^{) and said end area} front of the outer tube main body, and said belt-shaped collapsed annular fixing zone (106) is oblique to a central axis of said tubular zone (42, 142). A balloon catheter (1, 10, 100, 110, 130, 160, 170) according to claim 1, wherein said outer tube part (2) is formed entirely integral with said balloon part (4, 104) by using the same material as the one to be used for said balloon part (4, 104). A balloon catheter (1, 10, 100, 110, 130, 160, 170) according to any one of claims 1 to 2, wherein said bulging area (40, 140) of said balloon part (4, 104 ) has an elastically deformable zone, a front side tapering zone (73), provided forward of said elastically deformable zone, tapering towards a front end thereof by a diameter thereof and is substantially elastically undeformable, and a rear-side tapering area, provided rearwardly from said elastically deformable area, tapering towards a rear end thereof by a diameter thereof and is substantially elastically non-deformable. 4. A balloon catheter (1, 10, 100, 110, 130, 160, 170) according to any one of claims 1 to 3, wherein ^{said balloon catheter (} 1 ^, 10 ^, 100 ^, 110 ^{, 130, 160, 170) is used to occlude a blood vessel.} A balloon catheter (1, 10, 100, 110, 130, 160, 170) according to claim 3 or 4, wherein said front side tapering zone (73) of said balloon portion (4, 104) is formed as a thickness change zone gradually becoming thicker at a front end thereof, and said back side tapering zone of said balloon part (4, 104) is formed as a thickness change zone becoming gradually thicker to a rear end of it. 6 ^{. A balloon catheter (1, 10, 100, 110, 130, 160, 170) according to any one of claims 3 to 5, wherein said outer tube part (} 2 ^{) has an outer tube main body (} 22 ^, 102 ^{) extending from a rear end zone of said front side cuff zone (} 21 ^, 120 ^{) to a proximal end of said} balloon catheter (1, 10, 100, 110, 130, 160, 170) and is harder that said front side sleeve area; a value of bending load of three points A1 per unit of deflection in said expandable zone of said balloon part (4, 104), a value of bending load of three points A2 per unit of deflection in said zone of side sleeve front, and a bending load value of three points A3 per deflection unit in a front side region of said outer tube main body (22, 102) are set to A1 <A2 <A3; a difference between said three-point bending load value A1 and said three-point bending load value A3 is set to no more than 300 mN / mm; and said three point bending load value A1 is set to no more than 50 mN / mm. ^{A balloon catheter (1, 10, 100, 110, 130, 160, 170) according to any one of claims 3 to} 6 ^{, wherein said outer tube part (} 2 ^{) has an outer tube main body (} 22 ^, 102 ^{) extending from a rear end zone of said front side cuff zone (} 21 ^, 120 ^{) to a proximal end of said balloon catheter (} 1 ^, 10 ^, 100 ^, 110 ^{, 130, 160, 170) and is harder than said front side sleeve area;} a bending load value of three points A1 per unit of deflection in said expandable zone of said balloon part (4, 104) and a value of bending load of three points A4 per unit of deflection in a border zone between ^{said front side sleeve area (} 21 ^, 120 ^{) and said outer tube main body (} 22 ^, 102 ^{) are set} to A1 <A4; a difference between said three-point bending load value A1 and said three-point bending load value A4 is set to no more than 50 mN / mm; and said three point bending load value A1 is set to no more than 50 mN / mm. 8 ^{. A balloon catheter (1, 10, 100, 110, 130, 160, 170) according to claim} 6 ^{or 7, wherein said} three-point bending load value A2 is set to no more than 100 mN / mm. ^{A balloon catheter (1, 10, 100, 110, 130, 160, 170) according to any one of claims} 6 ^to 8 ^{, wherein} said three-point bending load value A1 is set to no more than 40 mN / mm. A balloon catheter (1, 10, 100, 110, 130, 160, 170) according to any one of claims 1 to 9, wherein ^{a length of said front side cuff zone (} 21 ^, 120 ^{) of said outer tube part (} 2 ^{) is set at} no less than 2.5 times the length of said expandable zone of said balloon part (4, 104).